@font-face {
  font-family: "Inter";
  font-style: normal;
  font-weight: 400 700;
  font-display: swap;
  src: url("./fonts/inter-latin-variable.woff2") format("woff2");
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

/* Metric-matched fallback so the swap from Arial to Inter causes no layout shift. */
@font-face {
  font-family: "Inter Fallback";
  src: local("Arial");
  ascent-override: 90.2%;
  descent-override: 22.48%;
  line-gap-override: 0%;
  size-adjust: 107.4%;
}

:root {
  --color-bg: #f4f3f0;
  --color-surface: #ffffff;
  --color-text: #111110;
  --color-muted: #5c5a55;
  --color-rule: #1a1a18;
  --color-hairline: #d8d5ce;
  --color-accent: #d72207;
  --color-accent-soft: #fbe6e2;
  --color-good: #0b7a47;
  --color-warn: #8a5a00;
  --color-risk: #a10f1f;

  --space-1: 0.5rem;
  --space-2: 0.75rem;
  --space-3: 1rem;
  --space-4: 1.5rem;
  --space-5: 2.5rem;
  --space-6: 4rem;
  --space-7: 6rem;

  --radius-1: 0.125rem;
  --radius-2: 0.375rem;

  --hairline: 1px solid var(--color-hairline);
  --rule-strong: 2px solid var(--color-rule);
  --rule-accent: 0.4rem;
  --evidence-step: var(--space-4);

  --shadow-panel: 0 0.5rem 1.5rem rgba(17, 17, 16, 0.18);

  --z-nav: 50;
  --z-skip-link: 100;

  --max-width: 62rem;
  --measure: 46rem;

  --font-main: "Inter", "Inter Fallback", "Helvetica Neue", Arial, sans-serif;
  --leading-tight: 1.05;
  --leading-snug: 1.25;
  --leading-body: 1.6;

  --step-h1: clamp(2.75rem, 8vw, 6.5rem);
  --step-h2: clamp(1.75rem, 4vw, 3rem);
  --step-h3: 1.125rem;
  --step-lede: clamp(1.125rem, 2vw, 1.5rem);
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #100f0e;
    --color-surface: #1a1917;
    --color-text: #f4f3f0;
    --color-muted: #aba79f;
    --color-rule: #f4f3f0;
    --color-hairline: #383531;
    --color-accent: #ff6a4d;
    --color-accent-soft: #2a1714;
    --color-good: #5fcf95;
    --color-warn: #e6b85c;
    --color-risk: #ff8f99;

    --shadow-panel: 0 0.5rem 1.5rem rgba(0, 0, 0, 0.5);
  }
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--space-4);
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  margin: 0;
  font-family: var(--font-main);
  font-size: 1.0625rem;
  line-height: var(--leading-body);
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3,
h4,
p,
ul,
ol,
figure,
blockquote {
  margin-top: 0;
}

h1,
h2,
h3 {
  line-height: var(--leading-tight);
  letter-spacing: -0.02em;
  font-weight: 700;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
}

.skip-link:focus {
  left: var(--space-3);
  top: var(--space-3);
  z-index: var(--z-skip-link);
  background: var(--color-surface);
  border: var(--rule-strong);
  padding: var(--space-2) var(--space-3);
}

:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* Header */
.site-header {
  max-width: var(--max-width);
  margin-inline: auto;
  padding: var(--space-4) var(--space-4) var(--space-5);
}

.kicker {
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-accent);
  margin-bottom: var(--space-3);
}

h1 {
  font-size: var(--step-h1);
  margin-bottom: var(--space-4);
}

.lede {
  max-width: var(--measure);
  font-size: var(--step-lede);
  line-height: var(--leading-snug);
  color: var(--color-text);
}

.lede em {
  font-style: normal;
  background: var(--color-accent-soft);
  padding: 0 0.2em;
}

/* Page navigation (hamburger menu) */
.page-nav {
  position: relative;
  display: flex;
  justify-content: flex-end;
  margin-bottom: var(--space-5);
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  min-height: 2.75rem;
  padding: var(--space-1) var(--space-3);
  border: var(--hairline);
  border-radius: var(--radius-2);
  background: var(--color-surface);
  color: var(--color-text);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  user-select: none;
}

.nav-toggle::-webkit-details-marker {
  display: none;
}

.nav-toggle-bars {
  position: relative;
  display: block;
  width: 1.125rem;
  height: 2px;
  background: currentColor;
}

.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 100%;
  height: 100%;
  background: currentColor;
}

.nav-toggle-bars::before {
  top: -0.375rem;
}

.nav-toggle-bars::after {
  top: 0.375rem;
}

.page-nav[open] .nav-toggle-bars {
  background: transparent;
}

.page-nav[open] .nav-toggle-bars::before {
  top: 0;
  transform: rotate(45deg);
}

.page-nav[open] .nav-toggle-bars::after {
  top: 0;
  transform: rotate(-45deg);
}

@media (prefers-reduced-motion: no-preference) {
  .nav-toggle-bars,
  .nav-toggle-bars::before,
  .nav-toggle-bars::after {
    transition: top 0.18s ease, transform 0.18s ease, background 0.18s ease;
  }
}

.nav-panel {
  position: absolute;
  top: calc(100% + var(--space-2));
  right: 0;
  z-index: var(--z-nav);
  width: min(24rem, calc(100vw - 2 * var(--space-4)));
  max-height: min(80vh, 40rem);
  overflow-y: auto;
  background: var(--color-surface);
  border: var(--hairline);
  border-radius: var(--radius-2);
  box-shadow: var(--shadow-panel);
}

.nav-panel ul {
  list-style: none;
  margin: 0;
  padding: var(--space-2);
}

.nav-panel a {
  display: block;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-1);
  font-size: 1.0625rem;
  font-weight: 500;
  color: var(--color-muted);
  text-decoration: none;
}

.nav-panel a:hover,
.nav-panel a:focus-visible {
  color: var(--color-text);
  background: var(--color-accent-soft);
}

a {
  color: var(--color-text);
  text-decoration-thickness: 0.07em;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--color-accent);
}

/* Main / sections */
main {
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--space-4);
}

section {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-3);
  padding-block: var(--space-6);
  border-top: var(--hairline);
}

@media (min-width: 56rem) {
  section {
    grid-template-columns: 4rem minmax(0, 1fr);
    column-gap: var(--space-5);
  }

  .section-number {
    grid-row: 1 / span 2;
  }

  section > *:not(.section-number) {
    grid-column: 2;
  }
}

.section-number {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-accent);
  letter-spacing: 0.1em;
  margin: 0;
}

h2 {
  font-size: var(--step-h2);
  margin: 0;
  max-width: 20ch;
}

.prose {
  max-width: var(--measure);
}

.prose p {
  margin-bottom: var(--space-3);
}

.prose p:last-child {
  margin-bottom: 0;
}

.prose h3 {
  font-size: var(--step-h3);
  margin-top: var(--space-5);
  margin-bottom: var(--space-2);
}

.prose h3:first-child {
  margin-top: 0;
}

.standfirst {
  font-size: 1.25rem;
  line-height: var(--leading-snug);
  font-weight: 500;
}

strong {
  font-weight: 600;
}

.prose em {
  font-style: italic;
}

/* Section statement */
.statement {
  margin: var(--space-4) 0;
  max-width: var(--measure);
  border-top: var(--rule-strong);
  border-bottom: var(--rule-strong);
  padding-block: var(--space-4);
  font-size: clamp(1.25rem, 2vw, 1.5rem);
  line-height: var(--leading-snug);
  letter-spacing: -0.01em;
  font-weight: 600;
  text-wrap: balance;
}

/* Problem grid */
.problem-grid,
.direction-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr));
  gap: var(--space-3);
  max-width: var(--measure);
}

.problem-card,
.direction-card {
  border: var(--hairline);
  border-top: var(--rule-accent) solid var(--color-rule);
  border-radius: var(--radius-1);
  padding: var(--space-4);
  background: var(--color-surface);
}

.problem-card h3,
.direction-card h3 {
  font-size: var(--step-h3);
  margin-bottom: var(--space-2);
}

.problem-card p,
.direction-card p {
  margin: 0;
  color: var(--color-muted);
}

.direction-card[data-direction="up"] {
  border-top-color: var(--color-good);
}

.direction-card[data-direction="down"] {
  border-top-color: var(--color-risk);
}

/* Evidence stack */
.evidence-stack {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--space-2);
  max-width: var(--measure);
}

.evidence-layer {
  border: var(--hairline);
  border-left: var(--rule-accent) solid var(--color-rule);
  border-radius: var(--radius-1);
  padding: var(--space-4);
  background: var(--color-surface);
}

.evidence-layer[data-weight="strong"] {
  border-left-color: var(--color-good);
}

.evidence-layer[data-weight="medium"] {
  border-left-color: var(--color-warn);
  margin-inline-start: var(--evidence-step);
}

.evidence-layer[data-weight="judgment"] {
  border-left-color: var(--color-risk);
  margin-inline-start: calc(var(--evidence-step) * 2);
}

.evidence-tag {
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-muted);
  margin-bottom: var(--space-1);
}

.evidence-layer h3 {
  font-size: var(--step-h3);
  margin-bottom: var(--space-2);
}

.evidence-layer p:last-child {
  margin: 0;
  color: var(--color-muted);
}

@media (max-width: 38rem) {
  .evidence-layer[data-weight="medium"],
  .evidence-layer[data-weight="judgment"] {
    margin-inline-start: 0;
  }
}

/* Factor list */
.factor-list {
  list-style: none;
  margin: var(--space-4) 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  border-top: var(--rule-strong);
  max-width: var(--measure);
}

@media (min-width: 40rem) {
  .factor-list {
    grid-template-columns: 1fr 1fr;
    column-gap: var(--space-6);
  }
}

.factor-list li {
  display: grid;
  grid-template-columns: 0.4rem 1fr;
  column-gap: var(--space-3);
  align-items: start;
  padding-block: var(--space-3);
  border-bottom: var(--hairline);
  font-weight: 500;
  line-height: var(--leading-snug);
  text-wrap: balance;
}

.factor-list li::before {
  content: "";
  width: 0.4rem;
  height: 0.4rem;
  margin-top: 0.42em;
  background: var(--color-accent);
}

/* Scale table */
table {
  width: 100%;
  max-width: var(--measure);
  table-layout: fixed;
  border-collapse: collapse;
  border-top: var(--rule-strong);
  font-size: 0.9375rem;
  margin-block: var(--space-4);
}

caption {
  text-align: left;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-muted);
  margin-bottom: var(--space-2);
}

th,
td {
  text-align: left;
  vertical-align: top;
  padding: var(--space-2) var(--space-4) var(--space-2) 0;
  border-bottom: var(--hairline);
  overflow-wrap: break-word;
}

th:first-child,
td:first-child {
  width: 3.5rem;
}

thead th {
  font-size: var(--step-h3);
  color: var(--color-text);
}

tbody th {
  color: var(--color-accent);
  font-variant-numeric: tabular-nums;
}

td {
  color: var(--color-muted);
}

/* Complexity continuum */
.continuum {
  margin: var(--space-5) 0;
  max-width: var(--measure);
}

.continuum-svg {
  display: block;
  width: 100%;
  height: auto;
  font-family: var(--font-main);
}

.continuum-axis {
  stroke: var(--color-hairline);
  stroke-width: 1;
}

.continuum-grid line {
  stroke: var(--color-hairline);
  stroke-width: 1;
  opacity: 0.45;
}

.continuum-tick text {
  fill: var(--color-muted);
  font-size: 9px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  text-anchor: end;
  dominant-baseline: middle;
}

.continuum-margin {
  fill: var(--color-risk);
  fill-opacity: 0.14;
}

.continuum-divider {
  stroke: var(--color-muted);
  stroke-width: 1.5;
  stroke-dasharray: 4 3;
}

.continuum-divider-label {
  fill: var(--color-muted);
  font-size: 9px;
  font-weight: 600;
  letter-spacing: 0.04em;
}

.continuum-series {
  fill: none;
  stroke-width: 2.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.continuum-series-g {
  stroke: var(--color-text);
}

.continuum-series-r {
  stroke: var(--color-risk);
}

.continuum-node-g circle {
  fill: var(--color-text);
  stroke: var(--color-bg);
  stroke-width: 2;
}

.continuum-node-r circle {
  fill: var(--color-risk);
  stroke: var(--color-bg);
  stroke-width: 2;
}

.continuum-series-label text {
  font-size: 12px;
  font-weight: 700;
  dominant-baseline: middle;
}

.continuum-series-label-g {
  fill: var(--color-text);
}

.continuum-series-label-r {
  fill: var(--color-risk);
}

.continuum-head text {
  fill: var(--color-accent);
  font-size: 11px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.continuum-axis-title {
  fill: var(--color-muted);
  font-size: 9px;
  font-weight: 600;
  letter-spacing: 0.08em;
}

.continuum figcaption {
  margin-top: var(--space-2);
  font-size: 0.9375rem;
  line-height: var(--leading-snug);
  color: var(--color-muted);
}

/* Level track */
.level-track {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-2);
  max-width: var(--measure);
}

@media (min-width: 56rem) {
  .level-track {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.level {
  border: var(--hairline);
  border-radius: var(--radius-1);
  padding: var(--space-4);
  background: var(--color-surface);
  border-top: var(--rule-accent) solid var(--color-rule);
}

.level[data-level="auto"] {
  border-top-color: var(--color-good);
}

.level[data-level="agent"] {
  border-top-color: var(--color-warn);
}

.level[data-level="human"] {
  border-top-color: var(--color-risk);
}

.level h3 {
  font-size: var(--step-h3);
  margin-bottom: var(--space-1);
}

.level p.level-range {
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  margin-bottom: var(--space-2);
}

.level[data-level="auto"] .level-range {
  color: var(--color-good);
}

.level[data-level="agent"] .level-range {
  color: var(--color-warn);
}

.level[data-level="human"] .level-range {
  color: var(--color-risk);
}

.level p {
  margin: 0;
  color: var(--color-muted);
}

/* Mandatory grid */
.mandatory-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr));
  gap: var(--space-2);
  max-width: var(--measure);
}

.mandatory-card {
  border: var(--hairline);
  border-radius: var(--radius-1);
  padding: var(--space-3) var(--space-4);
  background: var(--color-surface);
}

.mandatory-card h3 {
  font-size: 1rem;
  margin-bottom: var(--space-1);
}

.mandatory-card p {
  margin: 0;
  color: var(--color-muted);
  font-size: 0.9375rem;
}

/* Negation list */
.negation-list {
  list-style: none;
  margin: var(--space-4) 0 0;
  padding: 0;
  max-width: var(--measure);
}

.negation-list li {
  padding: var(--space-3) 0 var(--space-3) var(--space-5);
  border-bottom: var(--hairline);
  position: relative;
  font-weight: 500;
}

.negation-list li:first-child {
  border-top: var(--hairline);
}

.negation-list li::before {
  content: "\00d7";
  position: absolute;
  left: var(--space-2);
  top: 50%;
  transform: translateY(-50%);
  color: var(--color-accent);
  font-size: 1.25rem;
  line-height: 1;
}

/* Footer */
.site-footer {
  max-width: var(--max-width);
  margin-inline: auto;
  padding: var(--space-5) var(--space-4) var(--space-7);
  border-top: var(--rule-strong);
  color: var(--color-muted);
}

.footer-summary {
  margin: 0 0 var(--space-4);
  max-width: 30ch;
  font-size: clamp(1.25rem, 3vw, 2rem);
  line-height: var(--leading-snug);
  letter-spacing: -0.02em;
  font-weight: 600;
  color: var(--color-text);
}

.footer-meta {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-muted);
}

.footer-attribution {
  margin: var(--space-2) 0 0;
  font-size: 0.8125rem;
  color: var(--color-muted);
}

.footer-attribution a {
  color: var(--color-muted);
  text-underline-offset: 0.18em;
}

.footer-attribution a:hover {
  color: var(--color-accent);
}

.footer-top {
  margin: var(--space-4) 0 0;
}

.footer-top a {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--color-text);
  text-decoration: none;
}

.footer-top a::after {
  content: "\2191";
  font-weight: 400;
}

.footer-top a:hover {
  color: var(--color-accent);
}